1. Field of the Invention
This invention relates to adjustable hinge installations for large heavy doors.
2. Description of the Prior Art
The present invention is particularly suitable for use in supporting large heavy doors on the outer shells of nuclear containment vessels. These outer shells are provided with a plurality of openings through which pipes and other conduits extend from a nuclear reactor contained within the outer shell. In order to provide proper shielding it is important that the outer shell openings closely enclose the projecting pipes and conduits. On the other hand, ready access must be available to the reactor itself in the region of these openings. Accordingly it has been the practice to provide large openings on the outer reactor shell when each projecting pipe or conduit penetrates the shell and to mount large doors on the shell on opposite sides of each projecting pipe or conduit with the doors being shaped so that when they are closed they extend closely around the pipe or conduit and when they are open they leave a large opening for access to the interior of the outer shell.
The doors for nuclear reactor containment shells are quite bulky and they may weigh as much as three thousand five hundred pounds (1600 kilograms). In addition, for reasons of safety it is important that these doors be mounted very accurately on the shell so that they can be swung between opened and closed position with very little effort and so that they will remain in any position to which they are set. It has been found difficult, however, to mount heavy doors on the outer shell of a nuclear reactor with a high degree of accuracy because the outer surface of the shell is curved and is generally uneven.
The prior art shows various door mounting arrangements which use adjustable hinges. Some examples of these adjustable hinges are shown in U.S. Pat. Nos. 398,636, 679,377, 1,484,536, 2,302,484, 2,581,104, 2,583,950, 2,683,279, 2,839,778 and 2,988,414. None of these hinges however can be adjusted firstly, to compensate for the uneveness of the support structure surface when the hinge is being installed, and secondly, to compensate for the vertical misalignment or tilting of the hinge pin due to the weight of the door after the hinge has been installed. Although U.S. Pat. Nos. 679,377, 2,581,104, and 2,988, 414 show hinges which are adjustable to control tilting of the hinge axis, these adjustments are limited in scope and are not suited for the compensation of support structure uneveness during hinge installation. Also any attempt to adjust the vertical alignment of the hinge axis in the above patents results in stress on the pivot bearing for the hinge pin which is unsuitable for the heavy door mountings with which the present invention is useful.